1. Field of the Invention
This invention relates to a tool comprising a blank and shank, bonded by thermocompression bonding, in particular, using gold as a bonding material, and a process for the production of the same. Such a tool is suitable for use as a bonding tool for tape automated bonding.
2. Description of Prior Art
As the prior art for the production of a tool comprising a blank and shank, there have been often used methods comprising brazing a blank consisting of, for example, cemented carbides, polycrystalline diamond, single crystal diamond, polycrystalline cBN, substrates consisting of sintered compacts containing one of Si, Si.sub.3 N.sub.4, SiC and AlN, as a main component, and/or composites thereof, coated with polycrystalline diamond by gaseous phase synthesis method (i.e. CVD diamond), etc. to a shank consisting of, for example, ferrous metals, nickel metals, cemented carbides, tungsten alloys, etc. with various brazing metals, for example, silver-type, gold-type, aluminum alloy-type, nickel type brazing metals, comprising sintering and bonding using a sintering metal and comprising mechanically fixing.
In the brazing method of the above-described bonding methods, it is required to use a brazing metal having a melting point ,of at least 300.degree. C. higher than the temperature at which the tool is used, from the standpoint of ensuring the bonding strength. Thus, there arises a problem that when using, as the blank, single crystal diamond, polycrystalline diamond or polycrystalline cBN, which tends to be deteriorated at 600 to 800.degree. C., in a tool to be used at 600.degree. C., for example, the use of a brazing metal having a melting point of 900.degree. C. or higher for bonding the blank with a shank, so as to ensure the bonding strength, results in deterioration of the blank of diamond or cBN during bonding, while the use of another brazing metal having a melting point of 600 to 800.degree. C., so as to prevent the blank from deterioration, results in that the bonding strength cannot be maintained during use of the tool at 600.degree. C.
In the sintering bonding method or mechanical bonding method, it is hard to bond a small-sized blank and thus it is required to secure a large-sized blank so as to render bonding well feasible.